112 PARTICULAR CONSIDERATIONS ON THE 



principles upon which, he operates, the result of his analysis 

 will show that they are combined precisely according to the 

 same plan as the elements of mineral bodies are known to be." 1 

 A particular fact is here worthy of attention : " The conversion 

 of fecula into sugar, as one of the ordinary processes of vege- 

 table economy, is effected by the production of a secretion 

 termed diastase, which occasions both the rupture of the starch 

 vesicles, and the change of their contained gum into sugar. 

 This diastase may be separately obtained by the chemist, and 

 it acts as effectually in his laboratory as in the vegetable or- 

 ganization. He can also imitate its effects by other chemical 

 agents/' 3 The same writer elsewhere adds, " No reasonable 

 ground has yet been adduced for supposing that, if he had the 

 power of bringing together the elements of any organic com- 

 pound in their requisite states and proportions, the result 

 would be any other than that which is found in the living 

 body. Every fresh discovery," he says, " is tending to break 

 down the barrier between the two classes of organic and 

 inorganic bodies, as far as regards their chemical combination." 3 

 [In point of fact, many organic compounds are now constantly 

 made from their elements in the laboratory.] 



An essential distinction between the vital and chemical 

 affinities becomes, in these circumstances, no longer maintain- 

 able. The predominant idea hitherto has been, that the vital 

 affinities are of a wholly peculiar nature, depending upon a 

 mystic something, to which the term vital principle was ap- 

 plied. But this idea is now on the decline. Admitting the 

 vital affinities, as powers superseding and counteracting or- 

 dinary chemical affinities, it is seen that the idea of a distinct 

 inscrutable principle on which they depend, is " both unsup- 

 ported by evidence and useless in the explanation of facts." 4 

 It is becoming evident that living structures result from the 

 action of a multitude of natural forces in combination 

 " gravity, cohesion, elasticity, the agency of the imponderables, 

 and all other powers which operate both on masses and atoms." 

 Professor Draper, of New York, in making this statement, says 

 " It is astonishing that in our days the ancient system which 

 excludes all connexion with natural philosophy and chemistry, 



1 Supplement to the Atomic Theory. 



2 Carpenter on Life, Todd's Cyclopedia. 



3 From the Prize Essay of Dr. Carpenter, (1838,) under the award of 

 the professors of the Edinburgh University. 



4 Alison's Principles of Physiology, quoted in the above Prize Essay. 



